PRESENTED BY:Munde Pooja S.

GUIDED BY:Prof. Sushil.V. Kulkarni

CONTENT

IntroductionWhat is Li-Fi?HistoryPresent scenarioIssue regarding Radio SpectrumWhy only VLCHow Li-Fi works?Li-Fi v/s Wi-FiAdvantagesDisadvantagesApplicationsAmazing fact about Li-FiConclusionReference

INTRODUCTION

Li-Fi is a VLC, visible light communication, technology developed by a team of scientists including Dr Gordon Povey, Prof. Harald Haas and Dr Mostafa Afgani at the University of Edinburgh.

Li-Fi is now part of the Visible Light Communications (VLC) PAN IEEE 802.15.7 standard.

Li-Fi is typically implemented using white LED light bulbs. These devices are normally used for illumination by applying a constant current through the LED.

However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. Unseen by the human eye, this variation is used to carry high-speed data.

What is Li-Fi?

Li-Fi is transmission of data through illumination

by taking the fiber out of fiber optics by sending data through a LED Light bulb.

This varies in intensity faster than Human Eye can follow.

It is fast and cheep wireless communication system which is optical version of Wi-Fi.

In simple term Li-Fi can be thought of as a light based Wi-Fi.

That is ,it uses light instead of radio waves to transmit the information.

HISTORY

Professor Harald Haas, from the University of Edinburgh in the UK, is widely recognised as the original founder of Li-Fi. He coined the term Li-Fi and is Chair of Mobile Comm.

at the University of Edinburgh and co-founder of pure LiFi.

The technology truly begun during the 1990’s in countries like Germany,Korea and Japan where they discovered LED’S could be retroffited to send information.

Harald Hass continues to wow the world with the potential to use light for communication.

HARALD HASS

PRESENT SCENARIO 1.4 MILLION 5 BILLION

PRESENT SCENARIO(CONTD…)

Radio Spectrum is congested but the demand for wireless data double each year.

Every thing ,it seems want to use wireless data but capacity is drying up.

There are some issues regarding Radio Spectrum:

1.Capacity 2. Efficiency 3.Availability 4.Security

WHY ONLY VLC

Radio Waves

Infrared Rays

Visible Rays

Ultraviolet Rays

X-RaysGama Rays

Gama rays cant be used as they could be dangerous.X-rays have similar health issues.Ultraviolet light is good for place without people, but other wise dangerous for the human body.Infrared, due to eye safety regulation, can only bse used with low power.

HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

WHO CAN REPLACE

RADIO WAVES FOR WIRELESS

COMMUNICATION ?

HOW LI-FI WORKS?

Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter.Operational procedure is very simple,if the LED is on,you transmit a digital 1,if it’s off you transmit a 0. The LED can be switched on and off very quicly,which gives nice opportunities for transmitting data .Hence all that is required is some LED’S and controller that code data into those LED’S.

All one has to do is to vary the rate at which LED’S flicker depending upon the data we want to encode.

Thus every light source will works as a hub for data transmission.

Fig.Data transmission using LED

Fig.Li-Fi environment

COMPARISON BETWEEN LI-FI AND WI-FI

LI-FI is a term of one used to describe visible light communication technology applied to high speed wireless communication. It acquired this name due to the similarity to WI-FI, only using light instead of radio waves.

WI-FI is great for general wireless coverage within buildings, and Li-Fi is ideal for high density wireless data coverage in confined area and for relieving radio interference issues, so the two technologies can be considered complimentary.

COMPARISON BETWEEN LI-FI AND WI-FI(CONTD..)

ADVANTAGES

Wi-Fi is great for general wireless coverage while Li-Fi is ideal for high density coverage in a confined region.

 It is believed that the technology can yield a speed more than 10 Gbps, allowing a HD film to be downloaded within 30 seconds.

Can be used underwater without radio interference because salt conduct electricity.

Transmission can be blocked by walls,so there is less risk for data leaking.

Can be safely used on planes because it does not interfere with radio equipment.

DISADVANTAGES

 Is that the light waves cannot penetrate walls.

In 2012, this technology was demonstrated and it was detectable upto a distance of 10 meter.

Light can’t pass through objects.

Interferences from external light sources like sun light,normal bulbs,and opaque materials in the path of transmission will cause interruption in the communication.

High installation cost of the VLC system.

Major challenge facing Li-Fi is how receiving device will transmit back to the transmitter.

APPLICATIONS

Li Fi technology is still in its infancy .However some areas where it seems perfectly applicable are:-

1- TRAFFIC LIGHTS

Traffic lights can communicate to the car and with each other. Cars have LED-based headlights, LED-based cack lights, and cars can communicate with each other and prevent accidents in by exchanging information.

APPLICATIONS(CONTD..)

APPLICATIONS(CONTD..)

2- INTRINSICALLY SAFE ENVIRONMENT

Visible Light is more safe than RF, hence it can be used in places where RF can’t be used such as petrochemical plants.

APPLICATIONS(CONTD..)

3-AIRLINESWhenever we travel through airways we face the problem in communication media,because the whole airways communication are performed on the basis of radio waves.To overcome this drawbacks on radio waves,Li-Fi is introduced.

APPLICATIONS(CONTD..)

4-HOSPITALS

APPLICATIONS(CONTD..)

5-ON OCEAN BEDSLi-Fi can even work underwater were Wi-Fi fails completely ,thereby throwing open endless opportunities for military or navigation operations.

AMAZING FACT ABOUT LI-FI

Every light source in homes and offices could potentially be a “Li-Fi” within 20 years.

When this technology becomes feasible like the Wifi, then our life will be awesome on earth.

   “This is the technology that could start to touch every aspect of human life within a decade.”

   

CONCLUSION

The possibilities are numerous and can be explored further. If this technology can be put into practical use , every bulb can be used something like a Wi-Fi hotspots to transmit wireless data and we will proceed towards the cleaner, greener, safer and brighter future..

REFERENCES

1.http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=778&title%20=%20Li-Fi%3A+A+New+Paradigm+in+Wireless+Communication&b_type=new&id=12042

2. http://en.wikipedia.org/wiki/Li-Fi

3. International Journal of advances in computing & communications, vol 1, 2013,page no-12www.ijacc.org

THANK YOUANY QUERIES……..